Combined telephone and alarm system.



No. 825,624; PATENTED JULY 10, 1906'. H. G. WEBSTER.

COMBINED TELEPHONE AND ALARM SYSTEM.

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ATENTED JULY 10, 1906.

3. G. WEBSTER. COMBINED. TELEPHONE AND ALARM SYSTEM.

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PATENTBD JULY 10, 1906.

-H. G. WEBSTER. COMBINED TELEPHONE AND ALARM :SYSTBM.

APPLICATION FILED J ULY11, 1904 arana OFFICE.

HARRY G. WEBSTER. OF CHICAGO, ILLINOIS. ASSIGNOR TO MILO G. 'KELLOGG. OF CHICAGO, ILLINOIS.

COMBINED'TELEPHONE AND ALARM SYSTEM.

Specification of Letters Patent.

Patented {uly 10, 1906;

Application filed July 11,1904. Serial No. 216,082.

To all whom it may concern:

Be it known that I, HARRY G. lVEBsTER, a citizen of the United States, and a resident of Chicago, county ofCook, and State of Illinois, have inventeda certain new and useful Improvement in a Combined Telephone and Alarm System, of wluch the following is a I full, clear, and concise description, reference a an improvement upon a system proposed exchange.

heretofore in which the circuits are at all times available for the transmission of alarmsignals without regard to their telephonic use, in which any derang' dent of a circuit which would interfere with such signal is antomatically indicated at the alarm-receiving station, in which there is no interference with telephonic conversation or signaling except upon the sending of an alarm-signal, and which is so arranged that it may be quickly and systematically embodied in any circuit of a telephone-exchange system without disturbing the permanent wiring of the 7 In such a system it is necessary that there shall be no interference with the relay or other device normally under control of the subscriber and by means of whichhe signals the telephone operator in initiating a call. except when an alarm-signal is sent, in

which case such interference may be disregarded. In said system this condition is provided for by the use of a relay or electromagnet separate and distinct from the telephone-relay associated with the line-circuit and controlling the alarm-receiving mechanism.

In accordance with my present invention the use of this extra relay or electromagnet is dispensed with, and the mechanism which controls the telephone calling-signal also serves to control the alarm-receiving apparatus, each in its proper manner.

In a preferred embodiment of my present invention in a central-battery telephone-exchange system the mechanism referred to consists of a special relay at the exchange l l l l l l connected at all times with the line-circuit and'central source of current. This relay is provided with two sets of contacts and is so arranged that a relatively weak current through its winding will actuate one set of contacts, while the passage of a relatively strong current will actuate both sets. Relays of this character are well known, as those having two armatures with spring-tension adjustment for each or havingtwo armat-ures, one being of greater magnetic permeability than the other, or having a single armature arranged to assume two operative positions determined by the strength of the relay-magnet as distinguished from its normal position. The circuit of this relay is preferably normally closed through a high resistance and impedance in bridge of the line and includes the contacts of a makeand-break device controlled by the alarmsending mechanism. This alarm-sending mechanism may be of the character of the ordinary district messenger box released manually or automatically to break and make the normally closed circuit of the relay in a predetermined manner.

The alarm-receiving apparatus may consist of the ordinary telegraph-register or other responsive device in a local circuitcontrolled by those contacts of the relay which are actuated by either strength of current. The other set of relaycontacts controls the circuit of the calling-signal of the telephoneswitchboard and is actuated only when the circuit of the relay is closed through a relatively low resistance, as by the removal of the subscribers telephone from its hook switch. It is evident that in theorganization as thus outlined the operation of the alarm-receiving apparatus is determined by the interruption of current in the line-circuit by the alarm-sending device, whether this current be the relatively Weak one which is normally present in the line or the relatively strong current which is present during the use of the telephone. It is also evident that the presence or absence of the weak current will have no influence upon the opera; tion of the telephone calling-Si nal. It will also be seen that for commercia reasons only certain lines of a telephone systemwould 0rdinarily be arranged for transmittin alarmsignals and that such lines would e scattered throughout the exchange rather than confined to any particular group. In order to avoid changing any of the permanent wir-' ing of the exchange and to facilitate connecparatus R, and the special relay F are in 1-.

cated in a conventional manner only, as I am not limited to any particular construction for these Well-known instrumentalities.

Figure 1 shows two complete line-circuits 'with regular cord connecting apparatus as embodying my invention in that type of telephone systems in which the line or calling signal is controlled by a relay permanently conheated with the line and in which the signal is efi'aced by being brought into shunt of the supervisory cord-signal upon the insertion of a connecting-plug. Fig. 2 indicates the mechanical structure of one form of the special relay F. Figs. 3 and 4 illustrate my invention n connection with that exchange system in which the local circuit of the callingsignal is interru ted bya relay operated over a third or local wire, Fig. 5 indicating the cord-circuit adapted for such a system.

' Fi s. 6 and 7 illustrate arrangements of wires of current-supply and comprisin an terminals to provide for systematically associating any set of special alarm apparatus with any line of an exchange system.

Like characters refer to like parts in the several figures.

In Fig. 1 the subscribers stations A and B are provided with the usual apparatus, adapted, preferably, for use with a central source a receiver r and transmitter t in a circuit w normally open at the hook-switch h, the bell band condenser 0 being in permanent bridge of the line. The limbs 1 and 2 of the line extend to the central office and are there connected to the 'acksB 4 and by means of the windings of t e s ecial relay F to the central battery 0. he alarm-sending apparatus (indicated at M) may consist of any suitable mechanism adapter to control separable contacts included in either one or both of the line-limbs and may be released manually, mechanically, or, as indicated, by an electromagnet m in a local circuit with the thermostats or circuit-breakers The alarm-re ceiving apparatus consists of an ordinary tele graph-register or other responsive device in a circuit controlled by contacts 5 6 of relay 'F. The circuit of subscriber A is indicated as in its normal condition, the circuit of battery C and relay 13 being closed throu h the resistance and im' edance 1.

weak current existing in the circuit at this ciently to attract its 'ch stands he relatively.

time energizes the magnet of relayF sulfiarrnature contact-piece 5, and'thus maintain the circuit of the receiving device R but on account of its stiffer adjustrnent the armature oontact-piece 8 will not be attracted. the subscriber removes his telephone from its hook-switch a relatively strong current will then flow through the relay-windings, causing the actuation of contact 8 and the display of the signal 10; also, that the circuit of contacts 5 6 will still be maintained. The cord connecting apparatus being of the usual ty e, the insertion of answering;

plug P will ring the low-resistance supervisory signal 1 1 into parallel circuit with line signal 10 and in series with the relatively high resistance 15. This causes the eflacement of the said line-signal by the practical short circuit established around it, and the high resistance 15 prevents the illumination of the supervisory signal 11. In completing a connection the. operator tests and rings in the usual manner with the calling-plug O, and the supervisory signal 12 is displayed until the removal of the ceiver. The relatively strong current which then results causes the contact-piece 8 to be attracted and the circuit through the lowresistance coil 16 to be broken, effacing the signal "12, and the conversational circuit is completed by means of the cord-strands 13 1 1 and condensers d d. The supervisory signal 11 or 12 will remain eflaced until the subscrib er replaces his receiver. The normal weak current then being of insuilicie'nt strength.

to cause the continued attraction of armature-contact 8 it will return to the normal position shown, causing the display of the supervisory signal in the well-known manner. It is thus seen that the weak current which is normally-present in the circuit does not interfere with or control the display of the telephonesignals, but thatfthey are alone controlled in response to the'movement of the hook-switch by the strong current, which also serves to supply the subscribers transmitter. The contacts 5 6 in the circuit of the alarm-receiving apparatus R are maintained closed by either strength of current, however, and are only separated alter a complete interruption of current in the line, as determined by the o eration of the'alarm-send'ing a paratus. apparatus is indicated at as in operation. When the circuit of battery 18 is interrupted, as at f of line B, the mag- It is evident that whencalled subscribers renet in is deenergized, the retraction of its ar- This action on account dependent of the position of the subscribers hook-switch. It is also evident that the re lay F may be so constructed that its contacts 5 6 will not be actuated by the rapid alternations of the calling-generator G, as the condenser in the generator-circuit prevents the current of battery C from taking that path to ground, and consequently an alarmsignal may be properly received even during the time when an operator is calling the subscriber. The contact 20 and its connected wire indicate that the receiving device It may be in a normally open circuit, if desired. It will be understood that the resistances 15 16 while shown separately may be wound upon the relay-core, if desired, byso arranging them as not to interfere with the magnetic action of the relay.

Fig. 2 shows an arrangement of the relay F, its armature a, rocking upon the knife-edge e, being shown completely retracted, as during the interruption of all current in the line by the separation of contacts 19. In this figure the contact-springs are numbered to correspond with the contact-pieces indicated in Fig. 1. hen the normal weak current exists, the armature is attracted sufficiently to bring the forward end of spring 5 into contact with spring 6; but on account of the stiffness or tension of springs 6 and 8, which are united by the piece of insulation i, no further movement can take place until the relatively strong current is set up by the closing ofthe contacts of hook-switchh. The armature then becomes completely attracted, breaking contacts 8 9 and closing contacts 7 8, while still maintaining spring 5 in contact with spring 6, as previously described. The spring 5 has only slight tension and the armature (1 depends principally upon gravity for its complete retraction. Being sufficiently massive to be comparatively sluggish in its ac tion, it is not controlled by the rapidly-alternating current used in calling a subscriber. While :two separate windings are indicated, they are only necessary to balance the telephoneline, the operation of the relay being the same with a single winding, as indicated in Fig. 4.

Fig. 3 illustrates my inventionas embodied in a telephone-exchange of that type in which the calling-signal is etfaced by means of a re lay under control of the telephone operator. In this figure the alarm-sending mechanism is indicated conventionally at M, the subscribers apparatus at A, the alarm-receiving apparatus at R, and the special relay at F. In its operation this system differs from the system of Fig. 1 only in that the signal 10 is effaced by its circuit being opened at the contact of relay 39 when the operator inserts a connecting-plug into a jack 3 or 4.

Fig. 4 illustrates a modification of the last figure in which the relay F has a single winding and is connected between limb 2 of the line and the grounded side of battery 0, the line-limb 1 being connected to the live side of the battery tln'ough an impedance-coil 15. In this modification an accidental ground upon either line-limb of sufiiciently low resistance to interfere with the operation of the alarm or telephone signals will short-circuit the relay F, and the prolonged separation of its contacts 5 6 will cause an indication of this condition of accidental ground at the alarm-receiving apparatus.

Fig. 5 ing apparatus for use with the systems of Figs. 3 and 4. It differs from that of Fig. 1 in that the circuits of the supervisory signals 11 or 12 are completed through the relays 39 upon the insertion of a plug, the signal being short-circuited to prevent its display by the action of relay 21 or 22 when the latter is energized by current flowing through the subscribers transmitter and hook-switch contacts. In the system of these Figs. 3, 4, and 5, as in that of Fig. 1, the alarm receiving apparatus is controlled by the action of contacts 5 and 6 of relay F. They are main tained in their normal position by the normal weak current flowing through impedance I or by the strong current set up in the use of the telephone and are onlyseparated when the relay is deprived of all current by the opening of a linelimb at contacts 19 through the action of the alarm-sendin mechanism or accidentally through interference with the circuit.

Fig. 6 indicates the arrangement of wires and terminals by which the special relay F and alarm-receiving apparatus may be associated with any line of the telephone-exchange illustrated in Fig. 1. The line-limbs 1 and 2 on entering the exchange are connected by flexible jumpers 26 and 27 with the protective devices D on the main distributing rack. The permanent connections of all lines are thence to relay rack-terminals 28 and 29, intermediate distributing rack-terminals at w, and multiple jacks 3 3. l/Vires from the answering-jack 4 and its associated signal 10 are permanently wired to the intermediate rack-terminals at s and associated with the desired line in the well-known manner with flexible jumpers, as indicated by the wavy lines. The relay by which the subscriber ordinarily controls his line and supervisory signals is indicated at 'n, and it will be understood that this relay is used for all lines which have not the special apparatus. It is also understood that a number of special relays and alarmreceiving devices are to be so arranged that they may be associated with any desired line and from time to time chan ed to other lines,

as occasion demands. In this feature of my invention the wires from the relay F are permanently connected to special terminals at 7ron the intermediate distributing-rack in the manner indicated, the relay F being located shows well-known cord connectthe system of Figs. 3 and 5..

point, while the alarmat any convenient R is at the alarm-recelvreceiving apparatus ing station, which may be outside of the tele-- the regular connections of relay n have been I removed, as indicated at terminals 28, as has also the regular jumper indicated by the wavy line between terminals 31 and 32. The special connections for properly associating the relay F with. the line-circuit are the short wire 30 and the'four jumper-wires runnin from the terminals at k to terminals at w and 31, as indicated. It will be thus understood by those skilled in the art that the various combinations required in practice between alarm apparatus and elephone apparatus may be made in a speedy and workmanlike manner. several grounds indicated are or may be the exchange-return and also that the several batteries may be one and the same.

It is evident that my invention is not confined to the use of relay F, which controls the signal by means of local circuits associated with the armaturecontacts, but that other well-known equivalent arrangements may be employed.

While I have particularly described my invention with regard to certain details of construction and arrangement, it is evident that many modifications mightbe made therein by those skilled in the art without departing from its spirit, and I therefore do not wish to v be limited to the precise structures illustrated and described.

What I claim as new and novel, and'desire to secure by Letters Patent of the United States, is A 1. A combined telephone and alarm system comprising a circuit extending froma substation to an exchange, means at'the substation ior producing different electrical variations in said circuit, telephone and alarm I signals, an electromagnet at the exchange for controlling said signals responsive to certain variations in said circuit to actuate said telephone-signal and responsive to other varia'tions to actuate said alarm-signal, and

- means at the substation and exc ange' for holding conversation over said circuit.

2. A combined telephone and alarm system comprising a circuit extending from a substation to an exchange, means for supplying a relatively small current to said circuit, telephone signaling means for increasing said relatively small current, alarm-signaltransmitting means for decreasing said rela- It is to be understood that the tively small current, telephone and alarm signals, a single unitary means at the exchange for actuating said telephone-signal in response to cuit and for actuating said alarm-signal in response to said decreased current in said circuit, and means at the substation and exchange for holding conversation over said circuit.

3. A combined telephone and alarm system comprising a circuit extending from a substation to an exchange, means for supplying a relatively small current to said circuit,

telephone signaling means for increasing said relatively small current, alarm-signaltransmitting means for decreasing said relatively small current, telephone and alarm signals, an electromagnet at the exchange for controlling said signals responsive to the increased current in said circuit to actuate saidtelephone-signal and responsive to said decreased current to actuate said alarm-signal, and means at the substation and exchange for holding conversation over said circuit.

4. A combined telephone and alarm system comprising a circuit extending from a substation to an exchange, means for supplying a relatively small current to said circuit,

telephone signaling means for increasing said relatively small current, alarm-signal-trans mittmg means for interrupting said circuit,

the increased current in said err-- telephone and alarm signals, an electromagnet at the exchange for controlling said signals responsive to the increased current in said circuit to actuate said telephone-signal and circuit 1nterrupt1ons to responsive to said actuate said alarm-signal, and means at the substation and exchange for holding convensation over said circuit.

5. The combination of a-telephone linecircuit, a subscribers telephone, a high resistance and impedance, a source of current normally closed through said line-circuit and high resistance and, impedance, mechanism intermediate of said source and said resistance and impedance adapted to interrupt the circuit of said source, mechanism controlled.

in the use of the telephone to complete alowresistance shunt around said resistance and impedance, and an electromagnetic device in the line-circuit responsive to interruptions in said circuit to actuate an alarm-signal, and responsive to an increase of current in said circuit to actuate a telephone-signal, substantially as described.

6. The combination of a subscriber s telephone, a telephone-exchange, a line-circuit connecting the telephone with the exchange, means for normally maintaining a weak current in the line-circuit, means for increasing this current during the use of the telephone, and an electromagnetic device connected Withthe line-circuit and responsive to an interruption in the line-circuit to control a spean electromagnetic device connected with the line-circuit, responsive to a relatively strong current to control a telephone-signal at the exchange, and responsive to a relatively weak current to control the special signal, substantially as described.

8. A combined telephone and alarm system comprising a circuit extending from a substation to an exchange, a source of current included in said circuit, a relatively high resistance included insaid circuit to cut downthe current therein to a re atively small value, telephone signaling me us for decreasing the said relatively high re stance in said circuit, thereby increasing the aurrent therein, alarm-signal-transmitting cans for decreasing said current of relative y small value, telephone and alarm signal and a single unitary means at the exchange or actuating said telephone-signal in response to the increased current in said circuit and for actuating said alarm-signal in response to said decreased current in said circuit.

9. A combined telephone and alarlm system comprisinga circuit extending from a substation to an exchange, a source of current included in said circuit, a relatively high resistance included in said circuit to cut down the current therein to a relatively small value, telephone signaling'means for decreasing the said relatively high resistance in said circuit, thereby increasing the current therein, alarm signal transmitting means for decreasing said current of relatively small value, telephone and alarm signals and an electromagnet at the exchange for controlling said signals responsive to the increased current in said circuit to actuate said telephone-signal and responsive to said depreased current to actuate said alarm-signa tem comprising a circuit extending from a substation to an exchange, a source of current included in said circuit, a relatively high resistance included in said circuit to cut down the current therein to a relatively small value, telephone signaling means for decreasing the said relatively high resistance in said circuit, thereby increasing the current therein, alarm signal transmitting means for interrupting said circuit, telephone and alarm signals, and an electromag-' net at the exchange for controlling said signal responsive to the increased current in said circuit to actuate said telephone-signal and responsive to said interruptions to actuate said alarm-signal.

In witness whereof I hereunto subscribe my name this 30th day of June, A. D. 1904.

HARRY G. WEBSTER.

Witnesses JULLA M. BRrsToL, F, W. DUNBAR.

10. A combined telephone and alarm sys- 

